AJSM - 2026-08-11 - Journal Article
Longitudinal Quantitative Mapping of Meniscal Morphological and Signal Intensity Differences After ACL Surgery.
Barnes DA, Murray CJ, Movahhedi M, Beveridge JE, Kiapour AM, Murray MM, Fleming BC
Topics
Key Takeaway
Meniscal morphological and signal intensity abnormalities in the anterior medial and lateral menisci persist at 24 months post-ACL surgery, failing to normalize toward the contralateral limb across all three time points.
Summary Depth
Choose how much analysis to show on this article page.
Summary
This study used quantitative CISS MRI to compare cross-sectional area and normalized signal intensity of medial and lateral menisci between surgical and contralateral limbs at 6, 12, and 24 months after ACL surgery in 82 patients (median age 17.6 years; 57 ACL restoration, 25 ACL reconstruction). The anterior medial and lateral menisci on the surgical side demonstrated persistently elevated CSA and signal intensity versus the contralateral limb at all time points, while posterior medial meniscal CSA was smaller on the surgical side. At 24 months, neither CSA nor SI profiles approached contralateral limb values, refuting the hypothesis of progressive normalization.
Key Limitation
The contralateral limb is used as the normative reference, but ACL-injured patients have documented bilateral neuromuscular and loading asymmetries that may confound interpretation of 'normal' contralateral meniscal values.
Original Abstract
BACKGROUND
Meniscal tears are frequently associated with anterior cruciate ligament (ACL) injuries. Evaluating longitudinal changes in meniscal integrity using quantitative magnetic resonance imaging after ACL surgery may provide valuable insight into joint recovery and subsequent reinjury risk.
HYPOTHESES
(1) The cross-sectional area (CSA) and normalized signal intensity (SI) profiles of the lateral and medial menisci for the surgical knees would be greater than those of the contralateral uninjured knees observed at 6, 12, and 24 months after surgery. (2) The CSA and Constructive Interference in Steady State (CISS) SI profiles obtained at 24 months would be closer to those of the contralateral limb when compared with those of the 6- and 12-month time points.
STUDY DESIGN
Cohort study; Level of evidence, 3.
METHODS
Deidentified postsurgical CISS magnetic resonance imaging scans of patients (n = 82; median age 17.6 years; 42 females and 40 males; 57 ACL restoration and 25 ACL reconstruction) were analyzed. CSA and normalized CISS SI values were extracted from the lateral and medial menisci to create morphological profiles. Statistical parametric mapping was used to compare the CSA and normalized CISS SI profiles between the surgical and contralateral limbs to identify specific regions that were different among the menisci at 6, 12, and 24 months.
RESULTS
The CSA and normalized CISS SI profiles of the anterior region of the medial menisci and lateral menisci for the surgical knees were greater than those of the contralateral uninjured knees, observed at 6, 12, and 24 months after surgery, whereas the posterior region CSA of the medial menisci was smaller. The lateral meniscus on the operated limb had a larger CSA and higher normalized CISS SI values than the lateral meniscus in the contralateral limb. The CSA and CISS SI profiles obtained at 24 months did not approach those of the contralateral limb.
CONCLUSION
Significant changes occurred in both menisci after ACL surgery that did not return to baseline levels within 2 years. It is important to account for anatomic location when evaluating meniscal morphology in surgical knees and when evaluating the effects of ACL injuries on the surrounding tissues.